Imagine a cure-all that helps prevent cancer, weight gain and heart disease; one that can improve memory and athletic performance and even fend off colds. Now suppose that this panacea is pleasurable. It's not a daily pill, painful injection or bizarre-tasting tonic. And then imagine that only about 30 percent of you bother to take full advantage of this remedy.

You've likely guessed we're talking about sleep, and you know your body needs it, yet you're still depriving yourself: Nearly 60 percent of you log fewer than the seven to eight hours a night that experts say is optimal, according to our recent Self.com poll. Worse, more than 15 percent of you get by on fewer than six.

"Sleep is no different from diet or exercise," says Carol Ash, D.O., a sleep specialist in Jamesburg, New Jersey. We know that eating 10 percent more calories a day can add 15-plus pounds to our frame in a year. But we fail to understand that sleeping 10 percent less carries a similar risk for weight gain. In fact, women who sleep five or fewer hours a night are one third more likely to gain 33 pounds over the next 16 years than those who get seven hours of slumber, the American Journal of Epidemiology reports.

And that's just for starters. It's best for our body to cycle through the five sleep stages four or five times a night: The first four stages are key to maintaining healthy metabolism, learning and memory; the fifth (rapid eye movement sleep, or REM) is important for regulating mood and forming emotional memories. Miss a cycle or two and our immune system, heart health, brain function and more can suffer Give it a rest! It's time to get the curative shut-eye you crave.

Beyond tired

Droopy eyelids and low energy are the least of your worries when you're sleep-deprived. If you aren't getting the seven to eight hours that's ideal, you can seriously compromise your health.

More than 8 hours Sadly, you can have too much of a good thing. Regularly amassing more than eight hours a night disrupts blood sugar levels, which makes type 2 diabetes a concern, according to findings in the journal Diabetes Care. And sleeping more than nine hours is linked to an increased risk of dying due to any cause, say researchers at the University of California at San Diego and elsewhere, possibly because other health conditions that cause fatigue are a factor.

Fewer than 7 hours You're three times more likely to catch a cold if you sleep fewer than seven hours per night than if you get eight, possibly because sleep helps regulate the body's response to infection. Weight gain also becomes a worry: We produce more of the appetite-promoting hormone ghrelin and less of the satiety-producing hormone leptin when we're low on sleep.

6 hours or fewer You may think you function fine on this little sleep, but snoozing six hours or fewer a night for a period of only two weeks will impair your memory, reaction time and general cognition in the same way that staying awake for up to 48 hours straight would, according to a study from the University of Pennsylvania School of Medicine in Philadelphia.

5 hours or fewer Averaging five hours or fewer of sleep weakens your body's ability to regulate blood sugar levels, which may double your risk for type 2 diabetes, according to Diabetes Care. And people who sleep five or fewer hours a night are 50 percent more likely to develop high blood pressure than are those who get more than six, possibly due to their elevated levels of the stress hormone cortisol, which strain the heart, the journal Sleep reports.